/Engine/Source/Runtime/SignalProcessing/Public/DSP/LateReflectionsFast.h
Retrieve the internal delay line data. The number of samples retrieved is limited to the number of samples in the internal buffer. That amount can be determined by calling "GetNumInternalBufferSamples()".
void PeekDelayLine ( int32 InNum, [FAlignedFloatBuffer](API\Runtime\SignalProcessing\DSP\FAlignedFloatBuffer) & OutSamples )